There is a need to provide wireless communications from inside a sealed steel freight container to an external receiver and an information processing device. ISO steel freight containers are commonly used to ship cargo via ships, trains and trucks. The typical dimensions of these containers are 20 feet long; 8 feet long, and 8 feet, six inches tall. These containers may be loaded with cargo and sealed shut in a foreign country. Several million cargo containers—about 95 percent of U.S. international trade—enter the United States every year through its 361 sea and river ports. Since Sep. 11, 2001, there has been a pronounced concern that terrorists might use the containers to sneak biological weapons or other arms into the country. This method allows government, port or shipping company officials to monitor a container's location—and determine whether it has been tampered with.
The shipment of sealed ISO containers raises security risks and concerns about the safety and integrity of the cargo during shipment. The large number of ISO containers that are shipped worldwide cannot all be readily opened and inspected at each port, rail yard and trucking depot. It is virtually impossible for security personnel to inspect the contents of all ISO containers in transit to ensure that the containers are not being used to smuggle dangerous or illegal products, and have not been opened and tampered with during transportation. A cleaver thief, smuggler or terrorist may gain access to an ISO shipping container in transit and open the container to steal goods from the container, or insert into the container illegal products, e.g., drugs, or a bomb. By closing and resealing the container, the thief, smuggler or terrorist may avoid detection and the tainted container may continue its journey to its intended final destination. Even if the container is not intentionally opened during shipment, the inside of the container may subjected to environmental conditions, e.g., heat and humidity, that can damage the cargo in the container. In view of these dangers and the difficulty with inspecting ISO containers in transit, there is an urgent requirement for techniques and systems to inspect ISO shipping containers that are automated and do not require the container to be opened.
Obtaining data about the cargo inside of a sealed ISO shipping container is problematic. The container is formed of steel which effectively blocks wireless electromagnetic signals. Wireless signals may be further blocked by contents and adjacent containers, especially while the containers are stacked on top of each other. The doors of the container have seals that block water and wind, but also block optical signals from emanating from the container. Accordingly, passing a signal trough the container without breaching the wall of the container is difficult.
Prior attempts to track ISO containers have generally involved placing labels or transmitters on the outside of the containers. These external labels and transmitters may be dislodged in transit, may become damaged by weather or collisions with other containers, and do not interrogate the cargo inside of the container.
To transmit an external signal from inside a sealed ISO container, a transmitter inside of the container has been directly connected to antenna that protrudes through the wall of the container. See, e.g., U.S. Pat. No. 6,492,904 at col. 15 and FIG. 11. Projecting an antenna through the container wall breaches the container and may not be acceptable for ISO compliant shipping containers. Accordingly, there is a long felt need for an non-obtrusive technique and system that monitors and collects data regarding the interior of ISO shipping containers and their cargo, and automatically conveys that data to an external data collection receiver without breaching the sealed container.